Method for tracking personnel and equipment in chaotic environments

ABSTRACT

A method for automatically calibrating and deploying a tracking system of the type used by emergency responders ( 10 ) at the scene of a chaotic event such as a fire or the like. Each firefighter ( 10 ) is issued a wireless tag ( 26 ) having a unique identification number. Personal details about the firefighter ( 10 ) are prerecorded in a central database ( 44 ). Every piece of equipment ( 12, 14, 16 ) is also issued a wireless tag ( 26 ), with details about that piece of equipment prerecorded in the central database ( 44 ). At the scene of an emergency, drop readers ( 30, 30′ ) are scattered about the area. The drop readers ( 30, 30′ ) sense the location and ID number of each wireless tag ( 26 ). The drop readers ( 30, 30′ ) communicate with the central database ( 44 ) via a wireless connection ( 46 ). A scene commander ( 18 ) interfaces with the central database ( 44 ) through a graphic user interface ( 48 ) to acquire real time information about the location and movement of all personnel and equipment at the response scene. The reported data may be superimposed over a map of the scene, and exported in the form of reports ( 52 ).

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. provisional applicationentitled Portable or Wearable System for Tracking Personnel andEquipment in Chaotic Environments having Ser. No. 60/740,475 and filedon Nov. 29, 2005.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The subject invention relates to a method for operating and deploying aresource tracking system of the type used by emergency responders at thescene of a chaotic event such as a fire or the like.

2. Related Art

Certain situations, such as emergencies and emergency drills orexercises, create chaotic environments where it can be difficult totrack and locate personnel and equipment. For example, if a building isevacuated, the security manager must know whether all of the workersinside the building have left and where they are presently located. Foranother example, an incident commander is placed in charge at a largefire with multiple fire departments responding. The incident commandermust know at all times what personnel and equipment are on site. In yetanother example, it may be necessary to track the exposure of people andobjects to toxic contaminants.

Emergency events usually happen at unknown and unplanned locations.There is no opportunity to set up equipment ahead of time. Under chaoticconditions, quick response time and data collection accuracy arecritical tools. The scene or incident commander is in need of aportable, rapidly deployable system which can help capture and providetracking information for response personnel and equipment with little orno set up effort.

The prior art has proposed various systems for locating tagged personneland equipment at the scene of an event. Generally, tags or othertransmitting devices are carried by the personnel or affixed to theequipment and transmit a signal that is received by one or more readerserected about the perimeter of a scene. These tags or other transmittingdevices are generally of two styles. In one style, the tag determinesits own location usually based on a feed from a navigational satellitesuch as GPS. The tag then transmits its known location to the reader,which acts as a relay passing the tag location on to a scene commanderequipped with a graphical user interface so that the position of all ofthe tags, and hence the associated resources, can be monitored. Tags ofthis first type are expensive devices and are useful only so long astheir ability to self-determine location is properly functioning. If thetag moves into an area where its ability to communicate with thenavigational satellite is interrupted, the functionality of the trackingsystem is compromised.

A second type of tag, much less expensive than the first type describedabove, transmits only an identification number and perhaps other basicinformation. The second type of tag does not have the capability, ordoes not rely on the ability, to self determine and transmit datacorresponding to its location. Rather, these systems rely upon acalibrated array of strategically arranged readers which sense andtriangulate the position of the tags, and then relay this calculatedposition back to the scene commander. While the use of these secondtype, low cost tags is generally preferred, this method of trackingpersonnel and equipment is disadvantageous because the readers must becarefully set up and calibrated prior to use. Such calibration mayrequire skilled technical people placing the readers at preciselocations about the scene of the chaotic event. Not only does thiscalibration step consume much valuable time, but also is not adaptableto the scene of a chaotic event because the scene can actually shiftduring its course. Take for example a fire, which migrates from onebuilding to the next.

Another drawback of prior art systems arise out of the inaccuratecalculation of tag locations. As can be imagined, obstructions presentin the chaotic scene, such as heavy concrete walls, thick metallicfeatures, and the like can affect the signal strength of wireless radiosignals passing therethrough. Likewise, electromagnetic reflectivesurfaces can affect the vector of radio signals emitted by the wirelesstags. These and other related factors can render false tag locationcalculations by the tracking system software. As a result, a scenecommander relying upon the calculated position of sensed tags within thescene may draw inaccurate conclusions because the actual position of asensed tag is not properly understood.

And yet another drawback found in prior art systems arises out of thegeneral inability to determine whether a tag is actually being trackedby the system at any given moment. Because such tags can be damagedthrough use, and also because the sensing range is usually limited,there exists a need to determine whether a tag being used by anemergency responder, at any given moment, is currently recognized by thetracking system.

SUMMARY OF THE INVENTION

The subject invention overcomes the shortcomings and disadvantages foundin prior art systems by providing a method for automatically calibratinga tracking system of the type used by emergency responders at the sceneof a chaotic event, such as a fire or the like. The method comprises thesteps of affixing a wireless tag to each of a plurality of emergencyresources, each tag configured to broadcast a unique ID number viawireless signal. The method includes dispersing the resources togetherwith their affixed tags about the scene of a chaotic event over agenerally defined area. The method also includes placing a first dropreader device within the generally defined area of the scene, assigningthe first drop reader an absolute position relative to the scene from areference input external to the tracking system, and receiving in thefirst drop reader at least one ID number from a sensed first one of thetags. The orientation of the sensed first tag is determined relative tothe first drop reader, and then the absolute position of the sensedfirst tag is calculated relative to the scene by its relationship withthe assigned absolute position of the first drop reader. The method goeson to include the step of placing a second drop reader device within thegenerally defined area of the scene and spaced from the first dropreader, receiving in the second drop reader at least one ID number froma sensed second one of the tags, and orienting the sensed second tagrelative to the second drop reader. The improvement comprises orientingthe second drop reader relative to the first drop reader and thendetermining the absolute position of the second sensed tag relative tothe scene by its sequenced relationship with the assigned absoluteposition of the first drop reader.

Thus, the subject method for automatically calibrating a tracking systemrequires only one of two or more drop readers to be located on the sceneby reference to an external input. The second and any additional dropreader devices can be calibrated based on their relative position to thefirst drop reader. This feature enables the quick and relativelyunsophisticated deployment of drop readers about the scene, as well asthe relocation of drop readers, if needed, as the scene migrates duringthe course of a chaotic event.

According to a second aspect of this invention, a method is provided fordeploying a tracking system of the type used by emergency responders atthe scene of a chaotic event such as a fire or the like. The methodcomprises the steps of affixing a wireless tag to each of a plurality ofemergency resources, each tag configured to broadcast a unique ID numbervia wireless signal. The method includes dispersing the resourcestogether with their affixed tags about the scene of a chaotic eventoccurring over a generally defined area, placing at least one dropreader device within the generally defined area of the scene,determining an absolute position of the drop reader relative to thescene, receiving in the drop reader at least one ID number from a sensedone of the tags, orientating the sensed tag relative to the drop reader,calculating the absolute position of the sensed tag relative to thescene by its relationship with the absolute position of the drop reader,and repeating at regular intervals the step of calculating the absoluteposition of the sensed tag to monitor movement of the tag over time. Theimprovement comprises the step of comparing the change in position ofthe sensed tag over time to at least one predetermined physicalconstraint, and then automatically adjusting the calculated absoluteposition of the sensed tag relative to the scene when the predeterminedphysical constraint is violated.

According to this aspect of the invention, the tracking system is ableto determine and/or infer real time location of tags even amongst falsesignal receptions caused by obstructions and reflective surfacesaffecting signal strength and vectors emitted by the tags. A scenecommander is thereby provided with more reliable, real time informationconcerning the location of emergency resources.

According to yet another aspect of this invention, a method is providedfor tracking emergency responders at the scene of a chaotic event suchas a fire or the like. The method comprises the steps of affixing awireless tag to each of a plurality of emergency resources, each tagconfigured to broadcast a unique ID number via wireless signal over alimited range, dispersing the resources together with their affixed tagsabout the scene of a chaotic event occurring over a generally definedarea, placing at least one drop reader device within a generally definedarea of the scene, receiving in the drop reader at least one ID numberfrom a sensed one of the tags, orienting the sensed tag relative to thedrop reader, repeating at regular intervals the step of orienting thesensed tag to monitor movement of the tag over time, and affixing alight source directly to the tag. The improvement comprises illuminatingthe light source in response to the tag moving either into or out of thelimited range of the wireless signal.

According to this latter aspect of the invention, it is possible tovisually determine whether any given tag is being tracked by the system.If it is determined that a tag is not being tracked by the system,corrective measures can be pursued.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages of the present invention willbecome more readily appreciated when considered in connection with thefollowing detailed description and appended drawings, wherein:

FIG. 1 is a simplified illustration depicting a plurality of emergencyresources dispersed about the scene of a chaotic event;

FIG. 2 is a simplified perspective view depicting two drop readersaccording to the subject invention, one drop reader shown enclosed in aprotective box-like case, and the other drop reader shown with the casepartially broken away and its hinged lid open to expose directionalantenna and a control interface;

FIG. 3 is an illustrative view of one example of a wireless tagaccording to the subject invention affixed to a jacket and including alight source which is illuminated in response to the tag moving eitherinto or out of signal range;

FIG. 4 is a schematic illustration of the subject tracking system;

FIG. 5 is a simplified flow chart depicting an exemplary logic diagramof the auto-calibration and auto-positioning features of the dropreaders; and

FIG. 6 is a simplified flow chart depicting an exemplary logic sequencefor the use of non-traditional data to determine the location of asensed tag.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the Figures, wherein like numerals indicate like orcorresponding parts throughout the several views, an exemplary chaoticevent is graphically illustrated in FIG. 1. In this example, the chaoticevent takes the form of a burning building to which firefighters havebeen dispatched. However, as suggested previously, the chaotic event cantake many different forms and types, and is not limited to firefighting.As additional examples, chaotic events may include formal militaryinitiatives, building evacuations, contamination spills, policeinterventions, and other unplanned events. The example of a fire is usedthroughout the remainder of the description as merely illustrative of achaotic event in which emergency responders are dispatched to the scene.

In FIG. 1, a plurality of emergency response resources are deployed tothe scene of the chaotic event, which event occurs over a generallydefined area. The emergency resources include personnel, depicted hereas firefighters 10, as well as equipment which may take the form of agenerator 12, rescue tools 14 or a fire truck 16. Of course, these arebut representative examples. An incident or scene commander 18represents the person or persons responsible for managing the deployedresources, both personnel and equipment, at the scene of the chaoticevent.

A building 20 is shown ablaze, with one of the firefighters 10 directinga stream of water 22 into the flames. As is often the case, the scene ofthe emergency response may not be accessible from all sides. In thisillustration, the building 20 is shown backed by another structure 24which prevents access to the rear side of the building 20. As can beappreciated, in some situations only one or two sides of the building 20may be accessible to the emergency responders. In this example, threesides of the building 20 are accessible to the firefighters 10.

The invention here provides a method for automatically calibrating atracking system of the type used by emergency responders at the scene ata chaotic event regardless of how many sides of the building 20 can beaccessed. The tracking system allows the scene commander 18 or otherresponsible person to manage the deployment of resources 10, 12, 14, 16at the chaotic event. This systems is implemented by proactivelyaffixing a wireless tag 26 to each of the plurality of emergencyresources 10-16. Ideally, the tags 26 are affixed well in advance of thechaotic event. The wireless tags 26 are perhaps best illustrated in FIG.3, as comprising some small, durable device that can be attached to ajacket 28, or other article of clothing carried by a firefighter 10. Thetag 26 is equally conveniently affixed to equipment, such as thegenerator 12, the rescue tools 14 and the fire truck 16. Indeed, everypiece of equipment which is expedient for the scene commander 18 totrack, is affixed with a tag 26.

The tags 26 can be of any conventional type configured to broadcast aunique ID number via a wireless signal, including but not limited toRFID types. Such tags have been proposed in numerous forms, includingboth passive and active devices, any of which can be implemented withinthe context of this invention. Passive devices are those which react toan incoming electromagnetic signal, whereas active systems usuallycontain an internal energy source and actively broadcast to an externalreader. In addition to the unique identification number broadcast byeach tag 26, it is possible for the tag 26 to communicate informationwhich may be specific to the person or piece of equipment to which it isattached, or may comprise sensed data such as the ambient temperature,ambient oxygen level, time of day, etc.

The subject method for automatically calibrating a tracking system hereincludes placing a first drop reader device, generally indicated at 30,somewhere within the generally defined area of the response scene. Thefirefighters 10 may simply hand-carry the drop reader 30 to anyappropriate location at the scene. This may comprise setting the dropreader on a stable surface, throwing atop a roof, hanging it from atree, or any other location which the firefighter 10 may determineadvantageous. Once the first drop reader 30 has been placed, it isassigned an absolute position relative to the scene from a referenceinput external to the tracking system. Thus, the geographic location ofthe first drop reader 30 is provided so that it can be identified on amap of the scene. This assigning of an absolute position preferablycomes by way of a signal transmitted from multiple navigationalsatellites 32. Such navigational satellites 32 are commonly known as GPSor global positioning systems. Through the method of triangulation, theGPS satellite 32 tells the first drop reader 30 where it is absolutelypositioned relative to the geographic area of the scene. If the firstdrop reader 30 is unable to receive a signal from a GPS satellite 32,its absolute position can be assigned manually by the scene commander 18or an appropriate technician. Thus, if the first drop reader 30 does nothave a reliable GPS satellite 32 feed, the scene commander 18 can,either by estimation or by precise knowledge, assign the first dropreader 30 an absolute position relative to the scene. This is animportant step so that the tracking system is able to relate thelocation of sensed tags 26 in a graphically accurate manner.

Examples of the first drop reader 30 are depicted in FIG. 2 as portable,rugged, rapidly-deployable units including an internal power source suchas a battery or fuel cell. The drop reader 30 is fitted with one or moreantenna 34 which may be of the directional type. The antenna 34 arecapable of receiving wireless signals broadcasting the unique ID numbersfrom the wireless tags 26, together with any additional informationwhich may be transmitted by the tags 26. This may comprise an auto-IDreader of the RFID type, but other wireless configurations are alsopossible. Furthermore, the drop reader 30 includes a self-containedcontrol module, such as a portable computer, having some form of userinterface 36. Although a rather sophisticated graphical user interface36 is depicted in the drawings, it is also sufficient to equip the dropreader 30 with a simple LED arrangement to indicate activity and status.

The first drop reader 30 functions as a wireless networktransmitter/receiver, which may operate on a cellular modem platform, oron an 802.11g wireless hub configuration, or other suitable methodology.Status indicators such as LED lights may also be incorporated toindicate status and functionality. Additionally, the drop reader 30 maybe fitted with sensors including, but not limited to,attitude/orientation, temperature, oxygen, and so on. A software programrunning on the control module collects data from all of the attachedsensors and readers, and establishes a link to other drop readers and/orother available networks via wireless networking. All of thesecomponents are encased in a protective, box-like case 38. The case 38 isextremely rugged, weatherproof, heat resistant, lightweight, andincludes a carrying handle 40. The box-like construction of the case 38enables many drop readers to be conveniently stacked for storage in thefire truck 16, and then deployed with the ease of a handled tool box.

The unique ID number broadcast by each tag 26 is received in the firstdrop reader 30 where the contained software also orients the tag 26relative to the drop reader 30. In other words, using directionalantenna 34 and possibly other indicia such as signal strength, the firstdrop reader 30 determines where the sensed tag 26 is located relative toits own position. Then, a calculation is made to determine the absolutesolution of the sensed tag 26 relative to the scene by its relationshipwith the assigned absolute position of the first drop reader 30. Saidanother way, because the absolute position of the first drop reader 30is known, e.g., via the GPS satellite 32, and because the distance anddirection of the tag 26 relative to the first drop reader 30 isdetermined, a rather simple mathematical calculation can be made todetermine with a fair degree of accuracy the absolute position of thesensed tag 26 on a map of the scene. By this quasi polar coordinatemethod, all tags 26 deployed about the scene that are in sensing rangeof the first drop reader 30 can be located in absolute terms relative toa map of the scene.

A problem arises, however, in that the tags 26 and/or drop reader 30have a limited broadcast/sensing range. The scene of the chaotic eventmay be much larger and more widespread than the limited ranges of thewireless signals. Additional factors may include large obstructions inthe scene, like thick concrete or metallic walls, earthen embankments,buildings or the like. Further, certain types of reflective surfaces maycause the electromagnetic wireless signals to bounce and reflect inunpredictable ways. For all of these reasons, the first drop reader 30may be inadequate to receive the transmitted ID numbers from all of thetags 26 deployed about the scene.

The method of this invention also includes the step of placing a seconddrop reader 30′ within the generally defined area of the scene, andspaced apart from the first drop reader 30. As shown in FIG. 1, three ofthe second drop readers 30′ are shown. However, in actual practice, moreor less than three second drop readers 30′ may be deployed. The seconddrop readers 30′ are identical in every respect to the first drop reader30. The only distinction between the first drop reader 30 and the seconddrop readers 30′ is that the first drop reader 30 is assigned anabsolute position relative to the scene from the GPS satellite 32 or bythe scene commander 18. In the example of FIG. 1, only the first dropreader 30 includes a clear feed from the GPS satellite 32, and thereforeis the only drop reader whose absolute position is assigned. In thisexample, the second drop readers 30′ are unable to accurately determinetheir absolute position from a navigational satellite 32. As a result,they are demoted to a second drop reader 30′ instead of a first dropreader 30, and orient themselves via wireless signal 42 relative to thefirst drop reader 30. Thus, so long as one drop reader 30 is able toaccurately determine its position relative to the GPS satellite 32, orotherwise assigned from the scene commander 18, all of the remainingsecond drop readers 30′ orient themselves by wireless communication 42and calculation back to the first drop reader 30.

Preferably, enough drop readers 30, 30′ are scattered about the scene sothat their combined sensing ranges are able to receive ID numbers fromall of the deployed tags 26. Functioning exactly like the first dropreader 30 described above, the second drop readers 30′ also orient thesensed tags 26 relative to themselves using triangulation, vectordirection plus signal strength, or other techniques. If a single tag 26can be sensed by more than one drop reader 30, 30′ at the same time, itslocation relative to the scene can be determined with even greaterprecision using triangulation techniques built into the system software.

A central database 44 contains pre-recorded specifying information foreach unique ID number associated with the tags 26. The specifyinginformation includes details about the person or piece of equipment towhich each tag 26 has been assigned. In the example of a firefighter 10,details of his or her name, unit/station, skill level, special training,etc. will be recorded in the database 44 together with the ID number ofthe tag 26 assigned to them. In the case of equipment, details aboutthat tool are also recorded in the database 44. These details are allassociated with the ID number of their respective affixed tag 26. Awireless connection 46 is established between at least one, butpreferably several of the drop readers 30, 30′ for transmitting theinformation collected by the drop readers 30, 30′. Althoughillustratively depicted in FIG. 1 as a direct link, the wirelesscommunication 46 can be relayed through signal towers, a cell phoneconnection, the internet, or any other appropriate means. By thistechnique, it is not necessary that the database 44 be physicallypresent at the scene of the chaotic event. Rather, the database 44 mayreside in a secure, remote location.

The scene commander 18 possess a graphical user interface 48 such as atablet PC, laptop computer, PDA or other device. The graphic userinterface 48 communicates through a wireless connection 50 to thedatabase 44 so that the specifying information which has been associatedwith the sensed ID numbers from the tags 26 can be transmitted from thecentral database 44. Preferably, although not necessarily, thisinformation is superimposed over a map or other graphical representationof the scene. On the display, the scene commander 18 is able to locateand track every deployed resource 10-16. FIG. 4 is a schematic viewillustrating the relationship between the several components in thesubject tracking system. Data presented to the graphic user interface 48for the benefit of the scene commander 18 can be exported as reports 52for post event analysis and documentation.

FIG. 5 presents a flow chart schematically illustrating the logicsequence used to self-calibrate and position the various drop readers30, 30′. As depicted here, each drop reader 30, 30′ endeavors toestablish a reliable GPS signal so that its absolute position can beassigned to it. If it cannot accurately establish its position throughthe GPS signal, the drop reader endeavors to establish its positionrelative to another drop reader, either a first drop reader 30 oranother second drop reader 30′. By this method, its position isdetermined relative to other drop readers. Failing this, the drop readerwill request that its host, e.g., the scene commander 18, assign it anabsolute position upon the scene. This logic cycle is repeated endlesslyfor each drop reader 30, 30′ throughout the duration of the chaoticevent.

FIG. 6 represents a schematic flow chart and logic diagram through whichthe drop readers 30, 30′ accurately calculate the absolute position ofsensed tags 26 in view of physical constraints. Such physicalconstraints may include information known about the operating spaceitself, such as obstructions and reflective surfaces, as well as datapertaining to the tagged resource 10-16. This latter aspect may includephysical properties such as the last known mass, speed and direction ofthe tagged item. Thus, in referring to FIG. 6, it will be understoodthat the drop readers 30, 30′ repeat the step of calculating theabsolute position of sensed tags 26 at regular intervals. The shorterthe repeat interval, the more accurate the information as to change ofposition and rate of change. For purposes of this example, it may beassumed that the cycle is repeated every few seconds. The controlsoftware is able to monitor the movement of each tag 26 over timethrough this procedure. However, because of the reality of physicalconstraints at the scene, the sensed data may not reliably resolve theabsolute position of a tag at any given moment. For example, if thebroadcast signal from a particular sensed tag 26 is passing through aheavy brick wall prior to its reception by a drop reader 30, and thenthe person or object to which the tag 26 is attached steps clear of thewall so that the signal strength rapidly increases, the control softwareused to determine the absolute position of the sensed tag 26 mayinterpret the quick change in signal strength as a rapid change inposition. This not being the real case, the subject method compares eachcalculated change in position for a sensed tag 26 against predeterminephysical constraints which may include obstructions, reflective surfacesand physical properties about the tagged item. In the preceding example,the predetermined physical constraint may be the knowledge that a 250pound firefighter cannot traverse 100 feet in 2 seconds. The controllogic then automatically adjusts the calculated absolute position of thesensed tag 26 relative to the scene whenever the predetermined physicalconstraint is violated.

Thus, and referring again to the exemplary logic presented in FIG. 6,decision block 54 queries whether a current reading, as compared againsta prior reading, is possible and/or likely. If the question is answeredin the affirmative, the reported position of the tag 26 to the graphicuser interface 48 is updated. If the query is answered in the negative,the position of the tag 26 is recalculated using additionalenvironmental data including whatever information can be known about theoperating space itself and the tagged item. The recalculated position isthen queried in function block 56 for reasonableness. If therecalculated position is plausible, its position is updated to thegraphic user interface 48. If not, the software will estimate the mostlikely position for the tag 26 and then update the known environmentaldata which may include inferring an obstruction or reflective surfacewhich is contributing to unreliable data.

Referring again to FIG. 3, the tag 26 is shown including a light source58 affixed directly thereto. The light source 58 may be a light emittingdiode (LED) or other suitable, low energy consumption device. The lightsource 58 is illuminated in response to the tag 26 moving either into orout of sensing range. Thus, by quick visual inspection, a firefighter 10or other person can immediately determine whether a tag 26 is beingtracked by the system. In the case of the light source 58 illuminatingonly when the tag 26 moves out of range, it serves as a warning, whenlit, that the scene commander 18 is not aware of the location of thetagged item. In a converse example, where the light source 58illuminates only when it is being sensed by a drop reader 30, 30′,illumination of the light source 58 will indicate a safe condition. Inthis latter example, it may be advantageous to provide a green color tothe light source 58. In the former example, where the light source 58only illuminates when it moves out of range, it may be advantageous tocolor the light source 58 red. Of course, other combinations of colorsand lighting schemes are possible. An important feature, however, isthat the tag 26 can be visually inspected to determine whether it is oris not within read range of one of the drop readers 30, 30′ at any givenmoment. In the preferred embodiment of this invention, the light source58 maintains a generally constant intensity of emitted light regardlessof fluctuations in the strength of the wireless readers signal. Thus,the light source 58 does not act as a signal strength meter, but ratheras a “yes” or “no” indicator of participation in the tracking system.

The foregoing invention has been described in accordance with therelevant legal standards, thus the description is exemplary rather thanlimiting in nature. Variations and modifications to the disclosedembodiment may become apparent to those skilled in the art and fallwithin the scope of the invention. Accordingly the scope of legalprotection afforded this invention can only be determined by studyingthe following claims.

1. A method for automatically calibrating a tracking system of the typeused by emergency responders at the scene of a chaotic event such as afire or the like, said method comprising the steps of: affixing awireless tag to each of a plurality of emergency resources, each tagconfigured to broadcast a unique ID number via wireless signal;dispersing the resources together with their affixed tags about thescene of a chaotic event occurring over a generally defined area;placing a first drop reader device within the generally defined area ofthe scene; assigning the first drop reader an absolute position relativeto the scene from a reference input external to the tracking system;receiving in the first drop reader at least one ID number from a sensedfirst one of the tags; orienting the sensed first tag relative to thefirst drop reader; calculating the absolute position of the sensed firsttag relative to the scene by relationship with the assigned absoluteposition of the first drop reader; placing a second drop reader devicewithin the generally defined area of the scene and spaced from the firstdrop reader; receiving in the second drop reader at least one ID numberfrom a sensed second one of the tags; orienting the sensed second tagrelative to the second drop reader; and orienting the second drop readerrelative to the first drop reader and then determining the absoluteposition of the second sensed tag relative to the scene by itsrelationship with the assigned absolute position of the first dropreader.
 2. The method of claim 1 further including the step oftransmitting the ID number of the sensed first tag to a centraldatabase.
 3. The method of claim 2 further including the step ofassociating the ID number of the sensed first tag with pre-recordedspecifying information corresponding to the resource in the centraldatabase.
 4. The method of claim 3 further including the step oftransmitting the associated specifying information corresponding to theresource from the central database to a graphic user interface.
 5. Themethod of claim 1 wherein said step of assigning the first drop readeran absolute position includes transmitting an absolute position from anavigational satellite.
 6. The method of claim 1 wherein said step ofassigning the first drop reader an absolute position includes manuallysetting an assumed location.
 7. The method of claim 6 wherein said stepof manually setting an assumed location occurs only if the first dropreader is unable to accurately determine its absolute position from anavigational satellite.
 8. The method of claim 1 wherein said step offirst orienting the second drop reader relative to the first drop readeroccurs only if the second drop reader is unable to accurately determineits absolute position from a navigational satellite.
 9. The method ofclaim 1 further including the step of encasing the second drop readerdevice within a box-like protective case. 10 A method for deploying atracking system of the type used by emergency responders at the scene ofa chaotic event such as a fire or the like, said method comprising thesteps of: affixing a wireless tag to each of a plurality of emergencyresources, each tag configured to broadcast a unique ID number viawireless signal; dispersing the resources together with their affixedtags about the scene of a chaotic event occurring over a generallydefined area; placing at least one drop reader device within thegenerally defined area of the scene; determining an absolute position ofthe drop reader relative to the scene; receiving in the drop reader atleast one ID number from a sensed one of the tags; orienting the sensedtag relative to the drop reader; calculating the absolute position ofthe sensed tag relative to the scene by relationship with the absoluteposition of the drop reader; repeating at regular intervals said step ofcalculating the absolute position of the sensed tag to monitor movementof the tag over time; and comparing the change in position of the sensedtag over time to at least one predetermined physical constraint, andthen automatically adjusting the calculated absolute position of thesensed tag relative to the scene when the predetermined physicalconstraint is violated.
 11. The method of claim 10 wherein said step ofcomparing the change in position includes identifying physicalobstructions present within the scene of the chaotic event.
 12. Themethod of claim 10 wherein said step of comparing the change in positionincludes identifying reflective surfaces present within the scene of thechaotic event.
 13. The method of claim 10 wherein said step of comparingthe change in position includes recalling the last known mass, speed anddirection of the sensed tag.
 14. The method of claim 10 wherein saidstep of automatically adjusting the calculated absolute position of thesensed tag includes inferring the absolute position of the sensed tagbased on the last known data of the sensed tag.
 15. A method fortracking emergency responders at the scene of a chaotic event such as afire or the like, said method comprising the steps of: affixing awireless tag to each of a plurality of emergency resources, each tagconfigured to broadcast a unique ID number via wireless signal over alimited range; dispersing the resources together with their affixed tagsabout the scene of a chaotic event occurring over a generally definedarea; placing at least one drop reader device within the generallydefined area of the scene; receiving in the drop reader at least one IDnumber from a sensed one of the tags; orienting the sensed tag relativeto the drop reader; repeating at regular intervals said step oforienting the sensed tag to monitor movement of the tag over time;affixing a light source directly to the tag; and illuminating the lightsource in response to the tag moving either into or out of the limitedrange of the wireless signal.
 16. The method of claim 15 wherein saidstep of illuminating the light source includes energizing a lightemitting diode.
 17. The method of claim 15 wherein said step ofilluminating the light source includes maintaining a generally constantintensity of emitted light regardless of fluctuations in the strength ofthe wireless reader signal.
 18. The method of claim 15 further includingthe step of transmitting the ID number of the sensed tag to a centraldatabase.
 19. The method of claim 18 further including the step ofassociating the ID number of the sensed tag with pre-recorded personalinformation corresponding to the resource in the central database. 20.The method of claim 19 further including the step of transmitting theassociated personal information corresponding to the resource from thecentral database to a graphic user interface.